This invention is directed to a motor controller for a battery-powered electric motor. The motor controller described below prevents undue battery drains, reduces motor damage, and reduces battery damage.
It is known in the art to provide a delivery truck with a hydraulically powered lift gate. Such lift gates are typically raised by a hydraulic pump driven by an electric motor. The electric motor in turn is powered by the electrical system of the delivery truck.
On many occasions, the lift gate is used while the internal combustion engine of the delivery truck is not running. Under these conditions, it is the battery of the electrical system of the truck that supplies power for the electric motor. Extensive use of the lift gate can drain the battery to the point where the battery has insufficient power to restart the internal combustion engine of the delivery truck. This can leave the delivery truck and the driver stranded. Also, if the pump motor is used extensively without running the engine of the delivery truck, the battery can be drained to the point where the battery is damaged, shortening the life of the battery. Furthermore, running the pump motor at a low voltage can shorten the life of the motor.
Another prior-art problem relates to poor connections causing a high resistance between the battery and the pump motor. Such high resistance connections can cause the solenoid of the pump motor to oscillate or chatter.
The present invention is directed to a motor controller that overcomes some or all of the drawbacks of the prior art discussed above.